Alaindelon surprisingly resembles Queen lead singer Freddy Mercury. They share hairstyles, moustache and even attitude. However, Alaindelon is better built being quite muscular. He often wears sweatshirts along with boxer shorts.

Alaindelon is a very comical person. Even though he tries to remain serious, his uselessness usually puts him down. He is a dimensional demon capable of going in between dimensions. He also has the ability to open himself up in order for people to enter him and be able to travel alongside him. He also lacks physical strength, but seems to make up for it with incredible durability. Most demons at least make some attempt to conceal their powers while in the human world, but Alaindelon tends to use his transport ability fairly often, splitting himself open even in front of people (which causes a fair amount of shock or disgust).

He first appears faking his death floating down the river where Oga finds him. Beelzebub popped out of him making Oga his caretaker. Thought dead, he later appears to usually bug Oga and Furuichi. He later goes to live with the latter after finding him a noble person.